Rectifier



June 13, 1939.

J, SLEPIAN v RECTIFIER Filed May 21, 1936 a hbfer' Ouf/efs ATTORNE I NVENTOR -f05 0h 5/30/00.

WITNESSES:

Patented June 13, 1939 UNITED STATES PATENT OFFICE RECTIFIER VaniaApplication May 21, 1936, Serial No. 81,041

1 Claim.

This invention relates to discharge devices, and particularly to agaseous discharge device used as a rectifier.

It is an object of this invention to provide means whereby the-dischargewill not become stationary on any one spot of either electrode.

It is a further object of this invention to provide a dischargedevicerin which the discharge will be caused to move continually andprogressively over the surface of the electrodes.

It is a further object of this device to provide a discharge device withannular electrodes and with means for causing the discharge to moverepeatedly around the annulus.

1 It is a further object of this invention to provide an annular tubewith annular electrodes and to establish a radial magnetic field acrossthe gap.

It is a further object of this invention to provide water cooling meansfor the electrodes in 20 such a tube.

Other objects of the invention and details of the structure employedwill be apparent from the following description and accompanyingdrawing, in which:

25 Figure 1 is a central vertical sectional View;

and

Fig. 2 is a plan view partly in section and partly broken away.

In the drawing, a glass envelope I is shown of 30 annular shape filledwith any desired gas such as argon or mercury vapor, and containing apair of anodes 2 and 3, each of annular form, and a single cathode 4below them and also of annular form. A water inlet 5 and a water outlet6 pro- 35 vides for the water cooling of the anode 2. Similarly, aninlet I and an outlet 8 provides for the water cooling of the anode 3.The cathode is water cooled by an inlet 9 and an outlet I0. Each of theinlet or outlet conduits is sealed to the glass 40 of the envelope Iwhere it passes through the envelope walls and each of the waterconduits is connected by a coiled rubber hose to the pump or other watersupply. The coiled rubber in the Water conduit provides insulation in away fa- 45 miliar in the art.

The annular tube I is surrounded by a cup II of iron or other magneticmaterial which has a central spindle I2 of the same material. A coil I3wound on the spindle I2 is supplied with direct 50 current which may befrom an independent direct-current source or may be from the rectifiedcurrent supplied by the device. The source of power for the rectifiedcurrent is the transformer I5, the secondary of which has its terminalscon- 55 'nected to the anodes 2 and 3. As illustrated, the

connection is made to the pipes 5 and I. The midpoint of the secondaryof the transformer I5 is connected to the cathode 4. The connection isillustrated as made to the pipe 9.

A Tesla coil I6 is connected at one extremity to 6 the pipe 9 and so tothe cathode 4. The other extremity of the Tesla coil is connected to aneedle point I! inside the tube I and close to the cathode 4.

In the operation of the device, to start, the 10 button I4 is pushedrendering the Tesla coil active and causing sparks between the needlepoint I! and the cathode 4. Interrupted current in the primary of theTesla coil induces high potentials in the secondary, thus yielding thedesired sparks. This establishes a cathode spot on the cathode and thenthe voltages impressed upon the anodes 2 and 3 are rectified by theaction of the anodes and the cathode 4.

The voltage delivered by the transformer I5 to the anodes does notexceed 212 volts r. m. s. across the whole secondary. Thus the maximumvoltage between the cathode 4 and the negative anode never exceeds 300volts. This is not sufficient toestablish a reverse current ofsubstantial amount. When the anode becomes negative in the ionizedatmosphere in the tube I, it attracts positive ions. Thus there is builtup around the negative anode a sheath of space charge which presents agreat obstacle to current through the tube to that anode. Electrons fromthe negative anode do not neutralize said space charge because the anodebeing cold delivers very few electrons. The current to establish saidsheath does not exceed a few milliamperes. The same reason explains whycurrent does not flow from the positive anode to the negative one. Therethe current is always from the positive anode to the cathode 4.

In order that powerful currents may be handled by the device withoutdamage, the anodes are water cooled by water through the inlets 5 and 'Iwhich emerges through the outlets 6 and 8. A similar supply of watercools the cathode 4.

An arc current flow between the anode 2 and the cathode 4 when thepotential impressed by the transformer I5 is in the direction to makethe anode 2 positive. The arc thus formed will not be stationary norwill it play erratically over the surface of anode and cathode, but,because of the magnetic field between the spindle I2 and the wall I I ofthe cup, the arc will rotate about the spindle I2 as a center traversingthe annular gap between the anode 2 and the cathode 4 at a speed whichwill depend upon the current. strength in the arc and upon the magneticfield. The annulus which constitutes the space occupied by the said gapis thus all occupied at one time or another by the are.

When the potential induced in the secondary of the transformer l5reverses, the cathode spot on the cathode 4 will persist, but thecurrent will now flow to the anode 3. The are will continue to rotate,traveling around the annular gap in the same way as when the currentpassed between the anode 2 and the cathode 4.

The heating effect of the are at the surface of the cathode is not greatbecause the arc does not remain in any one spot long enough to produceany substantial efiect. Thus the cathode and anodes are kept cool and donot melt or waste away as would happen if the arc were not caused torotate.

Many modifications of the details of this device and many analogousapplications of the principle here explained will occur to those skilledin the art. I do not intend the specific illustration and description ofone embodiment of this invention to be considered as a limitation. Nolimitation is intended unless it is required by the prior art orexpressed in the claim.

I claim as my invention:

A rectifier comprising an envelope having a gaseous atmosphere, a hollowannular cathode and two hollow annular anodes spaced therefrom withinsaid envelope, all said electrodes being substantially coaxial, coolingmeans connected to each of said electrodes, and means for producing asubstantially radial magnetic flux across the space intermediate saidanodes and cathode.

JOSEPH SLEPIAN.

